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ESP8266 – AT Command Reference

ESP8266, in it’s default configuration, boots up into the serial modem mode. In this mode you
can communicate with it using a set of AT commands. I will present to you a reference
of all known AT commands that ESP8266 supports, explain what they do and how to use them.

Historically AT commands are based on the Hayes Command Set and these are no different.

AT Commands

Index of all known AT commands

Line termination

ESP8266 expects <CR><LF> or CarriageReturn and LineFeed at the end of each command,
but just<CR> seems to work too.

Command variants

Each command can have up to 4 variants changing the function of it. You can
chose between them by appending one of four possible values to the end of the
root command itself. These four appendices can have the following values
"",=<parameter|[parameters]>,"?",=?

Type
Example
Description

Test
AT+CIPSTART=?
Query the range of values (So far only AT+CWMODE=? uses it)

Query
AT+CMD?
Returns the current value of the parameter.

Set
AT+CMD=Parameter
Set the value of user-defined parameters in commands and run.

Execute
AT+CMD
Runs commands with no user-defined parameters.

Note:

Not all AT commands support all 4 variants.
[] = default value, not required or may not appear.
String values require double quotation marks, for example: AT+CWSAP="ESP756190","21030826",1,4.
Baud rate = 115200
AT instruction ends with “\r\n”

Commands

Variant
Command
Response
Function

Execute
AT
OK
Test if AT system works correctly

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Variant
Command
Response
Function

Execute
AT+RST
OK
Reset the module

ESP-01 Output after reset:

 ets Jan  8 2013,rst cause:4, boot mode:(3,7)

wdt reset
load 0x40100000, len 24444, room 16
tail 12
chksum 0xe0
ho 0 tail 12 room 4
load 0x3ffe8000, len 3168, room 12
tail 4
chksum 0x93
load 0x3ffe8c60, len 4956, room 4
tail 8
chksum 0xbd
csum 0xbd

ready

ESP-12 Output after reset:

\0x04B1\0x85 \0xff\0x13:'\0xe0;\0xcc;!G\0xfa\0x11\0xa9R\0xc6\0x83\0x01\0xd9\0x81
[Vendor:www.ai-thinker.com Version:0.9.2.4]

ready

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Variant
Command
Response
Function

Execute
AT+GMR
version, OK
Print firmware version

Parameters:

version: firmware version number

ESP-01 output:

00160901

ESP-12 output:

0018000902-AI03

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Variant
Command
Response
Function

set
AT+GSLP=time
time OK
Enter deep sleep mode for time milliseconds

parameters:

time: Time to sleep in milliseconds

Example：

AT+GSLP=1500

Note:

Hardware has to support deep-sleep wake up (Reset pin has to be High).

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Variant
Command
Response
Function

Execute
ATE0
OK
Disable echo (Doesn’t send back received command)

Execute
ATE1
OK
Enable echo (Sends back received command before response)

Note:

I haven’t had any luck with this command yet. Both ATE0 and ATE1 return no this fun.
ATE returns OK
This changed with ESP-12 where the command functions exactly as expected!

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Variant
Command
Response
Function

Test
AT+CWMODE=?
+CWMODE:(1-3) OK
List valid modes

Query
AT+CWMODE?
+CWMODE:mode OK
Query AP’s info which is connect by ESP8266.

Execute
AT+CWMODE=mode
OK
Set AP’s info which will be connect by ESP8266.

Parameters:

mode： An integer designating the mode of operation either 1, 2, or 3.
1 = Station mode (client)
2 = AP mode (host)
3 = AP + Station mode (Yes, ESP8266 has a dual mode!)

Notes:

ESP-12 came configured as host with ssid set to ESP_A0A3F2, no password, channel 1
You can use AT+CWSAP? to find the current settings.

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Variant
Command
Response
Function

Query
AT+CWJAP?
+ CWJAP:ssid OK
Prints the SSID of Access Point ESP8266 is connected to.

Execute
AT+CWJAP=ssid,pwd
OK
Commands ESP8266 to connect a SSID with supplied password.

Parameters:

ssid：String, AP’s SSID
pwd：String, not longer than 64 characters

Example：

AT+CWJAP="my-test-wifi","1234test"

Example `AT+CWJAP?`：

+CWJAP:"my-test-wifi"

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Variant
Command
Response
Function

Set
AT+CWLAP=ssid,mac,ch
+CWLAP:ecn,ssid,rssi,mac OK
Search available APs with specific conditions.

Execute
AT+CWLAP
AT+CWLAP:ecn,ssid,rssi,mac OK
Lists available Access Points.

Parameters:

ecn:
- 0 = OPEN
- 1 = WEP
- 2 = WPA_PSK
- 3 = WPA2_PSK
- 4 = WPA_WPA2_PSK
ssid: String, SSID of AP
rssi: signal strength
mac: String, MAC address

Note:

On ESP-01 I have had no luck with the set version of this command (AT+CWLAP=...). If you know what it does
please let me know.
On ESP-12, the Set version of the command allows to see if a certain SSID, with certain MAC on
certain channel exists. If it doesit is returned as one line of the Execute version of this command.

Example `AT+CWLAP`:

+CWLAP:(3,"CVBJB",-71,"f8:e4:fb:5b:a9:5a",1)
+CWLAP:(3,"HT_00d02d638ac3",-90,"04:f0:21:0f:1f:61",1)
+CWLAP:(3,"CLDRM",-69,"22:c9:d0:1a:f6:54",1)
+CWLAP:(2,"AllSaints",-88,"c4:01:7c:3b:08:48",1)
+CWLAP:(0,"AllSaints-Guest",-83,"c4:01:7c:7b:08:48",1)
+CWLAP:(0,"AllSaints-Guest",-83,"c4:01:7c:7b:05:08",6)
+CWLAP:(4,"C7FU24",-27,"e8:94:f6:90:f9:d7",6)
+CWLAP:(2,"AllSaints",-82,"c4:01:7c:3b:05:08",6)
+CWLAP:(3,"QGJTL",-87,"f8:e4:fb:b5:6b:b4",6)
+CWLAP:(4,"50EFA8",-78,"74:44:01:50:ef:a7",6)
+CWLAP:(0,"optimumwifi",-78,"76:44:01:50:ef:a8",6)
+CWLAP:(3,"BHQH4",-95,"18:1b:eb:1a:af:5b",6)
+CWLAP:(3,"NETGEAR49",-86,"84:1b:5e:e0:28:03",7)
+CWLAP:(3,"ngHub_319332NW00047",-56,"20:e5:2a:79:b1:2f",11)
+CWLAP:(3,"BFZR4",-73,"18:1b:eb:1d:c3:91",11)
+CWLAP:(1,"5FFVL",-82,"00:26:b8:b5:c0:f2",11)
+CWLAP:(3,"59G6D",-77,"00:7f:28:6d:91:7b",11)
+CWLAP:(3,"N16FU",-53,"20:cf:30:ce:60:fe",11)
+CWLAP:(3,"ITS",-82,"90:72:40:21:5f:76",11)
+CWLAP:(3,"ITS",-79,"24:a2:e1:f0:04:e4",11)

Example `AT+CWLAP="N16FU","20:cf:30:ce:60:fe",11`:

+CWLAP:(3,"N16FU",-53,"20:cf:30:ce:60:fe",11)

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Variant
Command
Response
Function

Execute
AT+CWQAP
OK
Disconnect ESP8266 from the AP is currently connected to.

Note:

After running this command, if you run AT+CWJAP? it still shows the AP you were connected to before.
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Variant
Command
Response
Function

Query
AT+CWSAP?
+CWSAP:ssid,pwd,ch,ecn OK
Query configuration of ESP8266 softAP mode.

Set
AT+CWSAP=ssid,pwd,ch,ecn
OK
Set configuration of softAP mode.

Parameters:

ssid: String, ESP8266’s softAP SSID
pwd: String, Password, no longer than 64 characters
ch: channel id
ecn:
- 0 = OPEN
- 2 = WPA_PSK
- 3 = WPA2_PSK
- 4 = WPA_WPA2_PSK

Example
AT+CWSAP="esp_123","1234test",5,3
AT+CWSAP? => +CWSAP:"esp_123","1234test",5,3

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Variant
Command
Response
Function

Execute
AT+CWLIF
[ip,other] OK
List information on of connected clients.

Parameters:

ip: IP address of a client connected to the ESP8266 softAP
other: Other info, look at example. I don’t know what it means yet.

Example (ESP-01):

AT+CWLIF

192.168.4.100,3fff50b4:3fff50ba:3fff50c0:3fff50c6:3fff50cc:3fff50d2

OK

Example (ESP-12):

AT+CWLIF

192.168.4.100,c0:ee:fb:25:33:ec

OK

I ran the command after connecting to the ESP8266 with my cellphone.

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Variant
Command
Response
Function

Set
AT+CWDHCP=mode,en
OK
Enable or disable DHCP for selected mode

Parameters:

mode:
- 0 : set ESP8266 as a softAP
- 1 : set ESP8266 as a station
- 2 : set both ESP8266 to both softAP and a station
en:
- 0 : Enable DHCP
- 1 : Disable DHCP

Note:

This command doesn’t seem to work on firmware 00160901 (ESP-01) nor
0018000902-AI03 (ESP-12).

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Variant
Command
Response
Function

Query
AT+CIPSTAMAC?
+CIPSTAMAC:mac OK
Print current MAC ESP8266’s address.

Execute
AT+CIPSTAMAC=mac
OK
Set ESP8266’s MAC address.

Parameters:

mac： String, MAC address of the ESP8266 station.

Example:

AT+CIPSTAMAC="18:aa:35:97:d4:7b"

Note:

This command doesn’t seem to work on firmware 00160901

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Variant
Command
Response
Function

Query
AT+CIPAPMAC?
+CIPAPMAC:mac OK
Get MAC address of ESP8266 softAP.

Execute
AT+CIPAPMAC=mac
OK
Set mac of ESP8266 softAP.

Parameters:

mac： String, MAC address of the ESP8266 softAP.

Example:

AT+CIPAPMAC=”2c:aa:35:97:d4:7b”

Note:

This command doesn’t seem to work on firmware 00160901

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Variant
Command
Response
Function

Query
AT+CIPSTA?
+CIPSTA:ip OK
Get IP address of ESP8266 station.

Execute
AT+CIPSTA=ip
OK
Set ip addr of ESP8266 station.

Parameters:

ip： String, ip address of the ESP8266 station.

Example:

AT+CIPSTA=”192.168.101.108”

Note:

This command doesn’t seem to work on firmware 00160901

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Variant
Command
Response
Function

Query
AT+CIPAP?
+CIPAP:ip OK
Get ip address of ESP8266 softAP.

Execute
AT+CIPAP=ip
OK
Set ip addr of ESP8266 softAP.

Parameters:

ip： String, ip address of ESP8266 softAP.

Example:

AT+CIPAP="192.168.5.1"

Note:

This command doesn’t seem to work on firmware 00160901

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Variant
Command
Response
Function

Test
AT+CIPSTATUS=?
OK

Execute
AT+CIPSTATUS
STATUS:status +CIPSTATUS:id,type,addr,port,tetype OK
Get information about connection.

Parameters:

status：
- 2: Got IP
- 3: Connected
- 4: Disconnected
id： id of the connection (0~4), for multi-connect
type： String, “TCP” or “UDP”
addr： String, IP address.
port： port number
tetype：
- 0 = ESP8266 runs as a client
- 1 = ESP8266 runs as a server

Note:

On ESP-01 this command returns STATUS:1 instead (no extra info, but status changes)
On 0018000902-AI03 this command returns STATUS:2 instead (no extra info, but status changes)

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Variant
Command
Response
Function

Set
AT+CIPSTART=type,addr,port
OK
Start a connection as client. (Single connection mode)

Set
AT+CIPSTART=id,type,addr,port
OK
Start a connection as client. (Multiple connection mode)

Test
AT+CIPSTART=?
[+CIPSTART:(id)(“type”),(“ip address”),(port)] OK
List possible command variations)

Parameters:

id: 0-4, id of connection
type: String, “TCP” or “UDP”
addr: String, remote IP
port: String, remote port

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Variant
Command
Response
Function

Test
AT+CIPSEND=?
OK

Set
AT+CIPSEND=length
SEND OK
Set length of the data that will be sent. For normal send (single connection).

Set
AT+CIPSEND=id,length
SEND OK
Set length of the data that will be sent. For normal send (multiple connection).

Execute
AT+CIPSEND

Send data. For unvarnished transmission mode.

Normal Mode

Parameters:

id: ID no. of transmit connection
length: data length, MAX 2048 bytes

Unvarnished Transmission Mode

Wrap return “>” after execute command. Enters unvarnished transmission, 20ms interval between
each packet, maximum 2048 bytes per packet. When single packet containing “+++” is received, it
returns to command mode.

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Variant
Command
Response
Function

Test
AT+CIPCLOSE=?
OK

Set
AT+CIPCLOSE=id
OK
Close TCP or UDP connection.For multiply connection mode

Execute
AT+CIPCLOSE
OK
Close TCP or UDP connection.For single connection mode

Parameters:

id： ID no. of connection to close, when id=5, all connections will be closed.

Note:

In server mode, id = 5 has no effect!

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Variant
Command
Response
Function

Test
AT+CIFSR=?
OK

Execute
AT+CIFSR
+CIFSR:ip OK
Get local IP address.

Parameters:

ip: IP address of the ESP8266 as an client.

Example `AT+CIFSR`:

10.101.10.134

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Variant
Command
Response
Function

Set
AT+CIPMUX=mode
OK
Enable / disable multiplex mode (up to 4 conenctions)

Query
AT+CIPMUX?
+CIPMUX:mode OK
Print current multiplex mode.

Parameters:

mode:
- 0: Single connection
- 1: Multiple connections (MAX 4)

NOTE:

This mode can only be changed after all connections are disconnected. If server is started, reboot is required.

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Variant
Command
Response
Function

Set
AT+CIPSERVER=mode[,port]
OK
Configure ESP8266 as server

Parameters:

mode:
0: Delete server (need to follow by restart)
1: Create server
port: port number, default is 333

NOTE:

Server can only be created when AT+CIPMUX=1
Server monitor will automatically be created when Server is created.
When a client is connected to the server, it will take up one connection，be gave an id.

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Variant
Command
Response
Function

Query
AT+CIPMODE?
+CIPMODE:mode OK
Set transfer mode,normal or transparent transmission.

Set
AT+CIPMODE=mode
OK
Set transfer mode,normal or transparent transmission.

Parameters:

mode:
0: normal mode
1: unvarnished transmission mode

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Variant
Command
Response
Function

Query
AT+CIPSTO?
+CIPSTO:time
Query server timeout.

Set
AT+CIPSTO=time
OK
Set server timeout.

Parameters:

time: server timeout, range 0~7200 seconds

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!!! Don’t run this unless you know what you’re doing !!!

!!! It will likely brick your device !!!

Attempts to self-update from the internet.

Variant
Command
Response
Function

Execute
AT+CIUPDATE
+CIPUPDATE:n OK
Start update through network

Parameters:

–n:

1: found server
2: connect server
3: got edition
4: start update

Example:

AT+CIUPDATE

+CIUPDATE: 1
+CIUPDATE: 2
+CIUPDATE: 3
+CIUPDATE: 4

\0x02\0x8cl\0x8el\0x8e\0x1cp\0x0c\0x8c\0xf2nn\0xee\0x00l\0x8c\0x8el`
\0x02\0x90\0x12\0x12nnl\0x8cl`\0x02\0x0e\0x02nr\0x8e\0x92\0x92n\0x0c\0x0c
\0x02\0x8c\0x92`\0x02`
\0xf2n\0x0c\0x0c\0x0c\0x9e\0xe0b\0x82nl\0x8c\0x0c\0x8c
\0xf2nn\0xee\0x00\0x0c\0x8e\0x0elp\0xf2n\0xe0\0x10\0x02\0x0c
\0x0cr\0x8c\0x9c\0x9c\0xe2\0xe0\0x0c\0x0c\0x0c
\0x0cb\0x0cn\0xe2|\0x02\0xec\0xecl\0x8c\0x0cb\0x8c\0xf2nn
...forever

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Variant
Command
Response
Function

Execute

+IPD,len:data
Receive network data from single connection.

Execute

+IPD,id,len:data
Receive network data from multiple connection.

Parameters:

id: id no. of connection
len: data length
data: data received

Note:

I have had no luck with this command so far.

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Sources

esp8266 GitHub Wiki

ESP8266 – AT Command Reference · room-15

ESP8266 – AT Command Reference

AT Commands

Index of all known AT commands

Line termination

Command variants

Note:

Commands

ESP-01 Output after reset:

ESP-12 Output after reset:

Parameters:

ESP-01 output:

ESP-12 output:

parameters:

Example：

Note:

Note:

Parameters:

Notes:

Parameters:

Example：

Example AT+CWJAP?：

Parameters:

Note:

Example AT+CWLAP:

Example AT+CWLAP="N16FU","20:cf:30:ce:60:fe",11:

Note:

Parameters:

Parameters:

Example (ESP-01):

Example (ESP-12):

Parameters:

Note:

Parameters:

Example:

Note:

Parameters:

Example:

Note:

Parameters:

Example:

Note:

Parameters:

Example:

Note:

Parameters:

Note:

Parameters:

Normal Mode

Parameters:

Unvarnished Transmission Mode

Parameters:

Note:

Parameters:

Example AT+CIFSR:

Parameters:

NOTE:

Parameters:

NOTE:

Parameters:

Parameters:

!!! Don’t run this unless you know what you’re doing !!!

!!! It will likely brick your device !!!

Parameters:

Example:

Parameters:

Note:

Sources

Example `AT+CWJAP?`：

Example `AT+CWLAP`:

Example `AT+CWLAP="N16FU","20:cf:30:ce:60:fe",11`:

Example `AT+CIFSR`: